Hydraulic actuators are employed in numerous industries in a wide variety of machines and applications, converting pressurized hydraulic fluid into linear work and motion, via a motion of a piston within a cylinder. Such actuators may be employed to move the linkages and work tools of various earthmoving machines, such as excavators and loaders. For example, hydraulic cylinders may be positioned between boom, stick and bucket of a hydraulic excavator, allowing the bucket to be raised, lowered, and tilted between various positions as part of ordinary operations. These actuators may also be employed in steering mechanisms of various machines, for example, between the front and rear frames of loaders and motor graders to control articulation, or to control wheel position in off-highway trucks.
It may be desired to determine a position of the piston in the cylinder of the piston-cylinder assembly. Typically, this is achieved by using a sensor with the piston-cylinder assembly. In certain cases, the hydraulic fluid in the piston-cylinder assembly is at a pressure which may be detrimental to the sensor. Therefore, it may be desired that the sensor is positioned outside the piston-cylinder assembly. U.S. Pat. No. 6,834,574 discloses a fluid-pressure actuated piston-cylinder assembly having a sensor capable of reading at least one indicia marking on a piston rod in order to determine the movement and specific location of the piston rod relative to cylinder. The sensor is housed within a sealing gland that is incorporated within the piston-cylinder assembly, and is isolated from the internal fluid pressure and external elements.